983 forum posts
A Sunday evening query for you all.
A well used wooden box contains a set of guides engraved for BSW from ¼" down, and BA from 0 -12.
This also contains a baseplate, with holes labelled 1st, 2nd, & 3rd, each with an adjacent slot, presumably for each of the three normal tapers in a set of taps.
There is also the actual business part, with a sliding rod, and chuck, which fastens in each of the three holes. There is a cam which engages in the relevant slot in the plate which, when the ball ended lever is moved, swings the whole assembly about a pivot point concentric with the round holes.
The very right hand corner of the box contains a little Tee handled bolt which forms the pivot point as well as attaching the arm to the baseplate. Seen here assembled with a ¼" BSF tap and its associated guide bush
There is an adjustable guide and 3+4 legged indexing collar, which slides the main bar and chuck back and forth as it is rotated. The knife edge guide is adjustable for right and left handed taps.
And finally a plan view showing the ball ended handle, which rotates the eccentric in the slot.
Has anyone ever seen one, or even better have some instructions?
Edited By peak4 on 27/01/2020 00:09:41
|Clive Foster||27/01/2020 00:25:11|
|1992 forum posts|
It may be worth looking at the instructions for the Clarkson Drill and Tap Grinding Attachment, find a copy here **LINK** .
Seems to me that your device uses the same sort of setting concept and generates similar moves to grind the tap lead.
Hafta say I'm not entierly clear on exactly how the Clarkson device is used and I've actually got one. Must try someday when I'm feeling patient.
474 forum posts
Nothing beats the human eye.
|not done it yet||27/01/2020 08:33:11|
|3940 forum posts|
Yes, and using them to read the instructions is often a last resort.
Clearly, in this instance, he has already been using his eyes - and engaging the little grey cells - but would appreciate some extra assistance from someone who actually knows...
|322 forum posts|
Looks very much like the forerunner of the Clarkson drill and tap grinder. The three positions on the baseplate would give taper, second and plug angles, the protractor thing sets the relief angle and the thing wilt four pegs is for four flute taps, you may have a two and three peg one somewhere. If you send me a PM i will send you a copy of the Clarkson booklet, can’t get pics to work on here.
|Andrew Johnston||27/01/2020 10:59:47|
5115 forum posts
When I used my Clarkson tap grinder I think I set the tap orientation by eye so that the cutting edge was more or less on the horizontal plane along with the tap axis. I don't think it's that critical. Not a great picture but this shows the general arrangement:
983 forum posts
Thanks for the replies thus far folks; I do have the Clarkson instructions, but whilst similar in idea, this does seem to differ a bit in the setting up. For instance, there are no stops on the swing handle to limit the cut.
I have a Clarkson grinder to mount it on, but I'd be guessing even about wheel height.
Also it seem to be designed for taps down to 10BA or 1/16" BSW, both of which I could make a complete hash of without instructions. (Typo above when I said 12BA)
Off out now to try and work out how to change a sidelight bulb in a Peugeot Expert.
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